Sam Duluk was banished from the parliamentary wing of the Liberal Party by the premier on Friday over allegations of inappropriate behaviour at a Christmas party on December 13.

He is accused of making inappropriate comments to SA-BEST MP Connie Bonaros and slapping her on the buttocks at Parliament House last year.

His conduct is now the subject of a police investigation and his lawyers have asked for the independent inquiry be halted while police inquiries are underway.

Mr Duluk's lawyer Matt Selley told The Advertiser he believed the investigation by private detective Paul Hocking was prejudicial to his client's potential legal proceedings.

"I intend to write to the speaker to express my grave reservations about the propriety of Mr Hocking continuing with his investigation until such time as police complete their adjudication and determine if charges are to be laid," he said.

"And if charges are to be laid, then Mr Hocking's investigation and report should be postponed until they are determined."

Mr Marshall reaffirmed on Monday that Mr Duluk was "no longer a member of the Liberal Party or the parliamentary Liberal team".

But he said a move on the investigation was not in his hands.

"Ultimately, this is a decision for the speaker not for the government of South Australia," he said.

Australian Associated Press